This invention relates to measuring power supply stability.
Ideal power supplies maintain a constant output over an infinite range of loads. Real power supplies, on the other hand, will deliver an output that varies with, for example, the load on the supply, temperature, and line-voltage. For voltage power supplies, as supply current requirements increase and supply voltages decrease, minimizing output voltage variations generally becomes more difficult.
This problem is particularly germane to the microelectronics industry, where each generation of devices tends to require more current to operate at lower voltages than the previous generation. Moreover, as the load current increases, the magnitude of the voltage droop due to parasitic impedance of the package, socket, and motherboard interconnects also increases. As a result, it has become increasingly difficult to maintain on-die supply voltage levels within windows in which device performance is acceptable.